The Russo-Japanese War of 1904-05, which began with the
Japanese naval attack on Port Arthur, had its roots in the simultaneous
determination of both Japan and Russia to develop 'spheres of influence'
in the Far East, mainly at the expense of China. Japan fought a very successful
war against the crumbling Chinese Empire in 1894-95 and imposed a severe
treaty. Japan demanded from China a heavy war indemnity, the island of
Formosa, and Port Arthur and its hinterland. The European powers, while
having no objection to the indemnity, did feel that Japan should not gain
Port Arthur, for they had their own ambitions in that part of the world.
Russia persuaded Germany and France to join her in applying diplomatic
pressure on the Japanese, with the result that Japan was obliged to relinquish
Port Arthur. Two years later Saint Petersburg forced the Chinese into
leasing Port Arthur to Russia, together with the Liaotung Peninsula on
which it stood. For Russia this meant the acquisition of an ice-free naval
base in the Far East to supplement Vladivostok. For Japan it was a case
of adding insult to injury.

The Boxer Rebellion of 1900 caused the European powers and
Japan to send troops to China to suppress the rebels. When the fighting
was over, Russian troops were occupying Manchuria. Russia promised to
withdraw these forces by 1903, but failed to do so, wishing to hold Manchuria
as a springboard for further expansion of her interest in the Far East.
Meanwhile Japan was heavily engaged in Korea, successfully increasing
her influence in that country. Russia also had interest in Korea, and
although at first Russians and Japanese managed to peacefully coexist,
it was not long before tensions on both sides led to hostilities. Negotiations
between the two nations began in 1901 but made little headway. Japan then
strengthened her position by forming an alliance with Britain. The terms
stated that if Japan went to war in the Far East, and a third power entered
the fight against Japan, then Britain would come to the aide of the Japanese.

During her negotiations with Japan, Russia did not expect
the Japanese to go to war. After all, Japan was a newly emergent country,
whose naval officers might have been trained in Britain and her army officers
in Germany, but several of those officers had begun their careers wearing
armor and brandishing swords. The Russian army was the world's most powerful,
or at least that is what the Russians believed. But the Japanese had other
ideas. Japan knew that they could not win a long war fought over a vast
expanse, but they could win a short localized war.